1. Field of the Invention
The present invention relates to a magnetic levitation sliding structure, and more particularly, to a magnetic levitation sliding structure, which can easily perform a sliding operation due to reduced friction between slide members and can have a reduced thickness.
2. Description of the Related Art
Recently, portable electronic devices such as mobile phones, cameras, portable multimedia players (PMPs), electronic dictionaries, electronic organizers, navigations, mini notebooks, and the like increasingly employ a sliding structure. The sliding structure enables such portable electronic devices to be easily manipulated and implemented.
FIG. 1 is a perspective view of an example of a general mobile phone 10 having a sliding structure. The general mobile phone 10 having the sliding structure comprises a receiver 20 including a screen 2 and a transmitter 30 including a manipulating unit 3 such as number keys. In order to speak into the general mobile phone 10 or transceive messages, the receiver 20 is slid up with respect to the transmitter 30. For a sliding operation, the general mobile phone 10 involves a conventional sliding structure 40 (see FIG. 2).
Operations of the conventional sliding structure 40 may be semi-automatically performed because a user also has to exert force for the sliding operation to be performed. In addition, when the conventional sliding structure 40 is fully closed or opened, the sliding operation completely depends on manipulation by the user, and this causes inconvenience to the user.
Generally, the transmitter 30 exposed due to the sliding operation of the sliding structure has too small of an area to include various function buttons in addition to the number keys. Therefore, additional buttons are generally disposed at the receiver 20, and also, as needed, the function buttons are disposed at side surfaces of the general mobile phone 10. As described above, the function buttons are not mainly disposed at a single area of the general mobile phone 10 and are separately disposed at several areas of the general mobile phone 10, and thus, button manipulation cannot be easily performed. In addition, in order to operate the function buttons, additional circuit substrates, signal lines for connecting the buttons, flexible printed circuit boards, and the like have to be provided.
FIG. 2 is a side elevation view of the general mobile phone 10 illustrated in FIG. 1 to explain the conventional sliding structure 40 disclosed in Korean Patent Application Publication No. 10-2005-0037649. The conventional sliding structure 40 includes sliders 41 and 42 at the transmitter 30 and the receiver 20, respectively, and the sliders 41 and 42 include magnets 43, 44a, and 44b. The magnets 43, 44a, and 44b are disposed to exert magnetic forces on each other, so that the sliders 41 and 42 can be relatively moved by operations of the magnets 43, 44a, and 44b. 
In the conventional sliding structure 40, friction between the sliders 41 and 42 occurs, thus hindering the sliding operation. More specifically, the receiver 20 slidingly moves with respect to the transmitter 30, and in the state illustrated in FIG. 2, the magnetic north pole of magnet 44a of the receiver 20 and the magnetic south pole of the magnet 44b of the receiver 20 contact the magnetic north pole of the magnet 43 of the transmitter 30 and the magnetic south pole of magnet 43 of the transmitter 30, respectively. As described above, like magnetic poles of the magnets 43, 44a, and 44b contact each other and thus repel each other, so that the sliding operation to slide up the receiver 20 with respect to the transmitter 30 cannot be easily performed. Accordingly, it is inconvenient for the user to manipulate the conventional sliding structure 40. In addition, when the receiver 20 is at an initial closed position against the transmitter 30, opposite magnetic poles of the magnets 44a and 43 contact each other and attract each other, and thus, a large force has to be exerted to slide up the receiver 20, which causes inconvenience for the user.
FIG. 3 is a cross-sectional view of another conventional sliding structure 50 disclosed in Korean Patent Application Publication No. 10-2005-0089584. The conventional sliding structure 50 illustrated in FIG. 3 includes a first slide member 51 and a second slide member 52 that can slide with respect to the first slide member 51. The first slide member 51 includes a first magnetic member 53 having a shape of a horseshoe magnet, and the second slide member 52 includes a second magnetic member 54 having the shape of the horseshoe magnet. The first and second magnetic members 53 and 54 are disposed in alternate positions to facilitate a sliding operation.
When the conventional sliding structure 50 having the aforementioned structure performs the sliding operation, the north poles of the first and second magnetic members 53 and 54 repel each other, and the south poles of the first and second magnetic members 53 and 54 also repel each other. In addition, at the same time, the magnetic south pole of the first magnetic member 53 and the magnetic north pole of the second magnetic member 54 attract each other. As described above, due to the attraction, the sliding operation cannot be easily performed, since an additional manipulation force is needed.
In addition, for sliding movement to occur, an interval between the first and second magnetic members 53 and 54 has to be guaranteed. However, due to external impacts or vibrations, the first and second magnetic members 53 and 54 may contact with each other and, due to this contact, friction may be increased during the sliding operation. In this case, a surface contact occurs between the first and second magnetic members 53 and 54, so that large friction is generated, and the sliding operation cannot be easily performed. In addition, at bending portions of the first and second magnetic members 53 and 54 where the first and second magnetic members 53 and 54 are not in alternate positions, repulsion decreases, so that the sliding operation cannot be easily performed.
Also, the two magnetic members 53 and 54 having the shape of the horseshoe magnet disposed in alternate positions occupy a large space, so that the thickness of the entire sliding structure increases. In addition, an operation of disposing the magnetic members 53 and 54 having the shape of the horseshoe magnet in alternate positions cannot be easily performed.